Cacciali Pier, KÖhler Gunther
Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Senckenberganlage 25, 60325 Frankfurt a.M., Germany Goethe-University, Institute for Ecology, Evolution & Diversity, Biologicum, Building C, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany Instituto de Investigación Biológica del Paraguay, Del Escudo 1607, 1425 Asunción, Paraguay.
Zootaxa. 2018 Jan 25;4375(4):511-536. doi: 10.11646/zootaxa.4375.4.3.
Tropidurus is a Neotropical genus of iguanoid lizards characterized by a conspicuously enlarged interparietal plate, the presence of gular folds, presence of infradigital keels, and the absence of femoral pores. Currently, 29 species are recognized within the genus, seven of which are present in Paraguay: T. etheridgei, T. torquatus, T. guarani, T. lagunablanca, T. spinulosus, T. tarara, and T. teyumirim. We generated genetic data based on two DNA mitochondrial markers (16S and COI) and one nuclear (PRLR) marker for all the seven Paraguayan species with the goal to identify the taxonomic relationships among taxa based on the intra- and interspecific genetic variation and the construction of molecular clusters. ML and BI analyses match in the recognition of two main clusters: groups torquatus and spinulosus, and within the torquatus group the differentiation between T. catalanensis and T. etheridgei is highly supported. Nevertheless, there is a complete lack of congruence between mitochondrial and nuclear genes in the topology within the spinulosus group. Tropidurus guarani and T. spinulosus are more differentiated from the remaining species of the spinulosus group with genetic p-distances from 4.0 to 6.0. Low distances were found between T. lagunablanca and T. tarara (1.0-1.1%), and slightly higher, among T. teyumirim, T. lagunablanca, and T. tarara (2.0-2.6% respectively). From a morphological perspective, species of the Tropidurus torquatus group are easily distinguished; but we found strong overlaps of scalation characters in the spinulosus group. We interpret the low genetic distances documented among the nominal taxa Tropidurus lagunablanca, T. tarara, and T. teyumirim as evidence for conspecificity. This hypothesis is supported by the lack of morphological characters that would diagnose any of the three taxa. Similarly, we found low genetic distances among populations assigned to the nominal taxa T. guarani and T. spinulosus, including samples from near the type locality of the former, and therefore we recognize only two species of the T. spinulosus complex in Paraguay: T. spinulosus and T. lagunablanca.
角蜥属（Tropidurus）是新热带界的一类鬣蜥科蜥蜴，其特征为顶间骨板显著增大、有喉褶、有指下嵴且无股孔。目前，该属已确认有29个物种，其中7种分布在巴拉圭：埃氏角蜥（T. etheridgei）、环纹角蜥（T. torquatus）、瓜拉尼角蜥（T. guarani）、拉古纳布兰卡角蜥（T. lagunablanca）、小刺角蜥（T. spinulosus）、塔拉腊角蜥（T. tarara）和泰尤米林角蜥（T. teyumirim）。我们基于两个线粒体DNA标记（16S和COI）和一个核标记（PRLR），为所有7种巴拉圭角蜥属物种生成了遗传数据，目的是根据种内和种间遗传变异以及分子聚类的构建来确定分类单元之间的分类关系。最大似然法（ML）和贝叶斯推断（BI）分析在识别两个主要聚类上结果一致：环纹角蜥组和小刺角蜥组，并且在环纹角蜥组内，加泰罗尼亚角蜥（T. catalanensis）和埃氏角蜥之间的分化得到了高度支持。然而，在小刺角蜥组内的拓扑结构中，线粒体基因和核基因之间完全缺乏一致性。瓜拉尼角蜥和小刺角蜥与小刺角蜥组的其他物种差异更大，遗传p距离在4.0到6.0之间。拉古纳布兰卡角蜥和塔拉腊角蜥之间的距离较低（1.0 - 1.1%），而泰尤米林角蜥、拉古纳布兰卡角蜥和塔拉腊角蜥之间的距离略高（分别为2.0 - 2.6%）。从形态学角度来看，环纹角蜥组的物种很容易区分；但我们发现小刺角蜥组的鳞片特征有很强的重叠。我们将拉古纳布兰卡角蜥、塔拉腊角蜥和泰尤米林角蜥这几个名义分类单元之间记录的低遗传距离解释为同种的证据。这一假设得到了缺乏能区分这三个分类单元中任何一个的形态特征的支持。同样，我们在归为瓜拉尼角蜥和小刺角蜥这两个名义分类单元的种群中发现了低遗传距离，包括来自前者模式产地附近的样本，因此我们在巴拉圭只识别出小刺角蜥复合体的两个物种：小刺角蜥和拉古纳布兰卡角蜥。
